1. Field of the Invention
The present invention is generally related to a fuel supply system for a marine propulsion device and, more particularly, to a method by which an intermediate holding tank is replenished with fuel based on the consumption of fuel from the intermediate holding tank as determined by the amount of fuel provided to a plurality of fuel injectors.
2. Description of the Prior Art
Many different types of fuel supply systems are known to those skilled in the art. In certain fuel systems, a vapor separator tank (VST) is provided as an intermediate holding tank from which fuel is pumped to the injectors of a fuel injected engine. Another pump, generally referred to as a lift pump, can also be provided to transfer fuel from an external tank to the vapor separator tank.
U.S. Pat. No. 4,809,666, which issued to Baltz on Mar. 7, 1989, describes a fuel feed system for supplying fuel to a combustion chamber of a first internal combustion engine and to a combustion chamber of a second internal combustion engine. The fuel feed system includes a fuel tank, a first fuel pump including an outlet, and an inlet communicating with the fuel tank. The system also includes a fuel vapor separator including a first outlet, a second outlet, and an inlet communicating with the first fuel pump outlet, a second fuel pump communicating with the fuel vapor separator first outlet and communicating with the first engine combustion chamber, and a third fuel pump communicating with the fuel vapor separator second outlet and communicating with the second engine combustion chamber.
U.S. Pat. No. 5,417,239, which issued to Ford on May 23, 1995, describes a fuel transfer control apparatus. The apparatus is used for automatically shutting off the transfer of fuel from an auxiliary tank to a main fuel tank in a motor vehicle having an auxiliary fuel tank, a main fuel tank including a receptacle for receiving fuel from an outside source, a conduit for receiving fuel from the auxiliary tank and an activating means for transferring fuel from the auxiliary tank to the main tank. The apparatus comprises a chamber having opposite ends and being positioned to receive fuel overflow from the main tank. It also comprises an inlet opening at one end of the chamber for receiving the fuel overflow into the chamber from the main fuel tank. In addition, it comprises a sensor in the chamber for sensing the level of fuel in the chamber and a switch operable between on and off positions and connected to and responsive to the sensor wherein the activating means is automatically turned off when the switch is moved to the on position for stopping the transfer of fuel.
U.S. Pat. No. 5,913,294, which issued to Takahashi et al on Jun. 22, 1999, describes an outboard motor fuel supply system. The outboard motor includes a simply structured fuel supply system of a smaller size and a longer life than prior fuel supply systems. The fuel supply system includes a delivery fuel tank carried by the outboard motor. The fuel is pumped from an external fuel supply tank carried by the watercraft to the delivery fuel tank by a low pressure fuel pump located within the outboard motor. The control system controls the low pressure fuel pump so that a predetermined level of fuel is maintained in the delivery fuel tank. The control system includes a fuel level detection sensor that detects the level of fuel within the delivery fuel tank and produces a corresponding signal indicative of the fuel level. A control unit circuit receives the fuel level signal and determines if the fuel level in the tank is higher or lower than a predetermined maximum fuel level. If the fuel level is determined to be higher than a maximum fuel level, the control unit circuit deactivates the low pressure fuel pump. If the fuel level is determined to be lower than the maximum fuel level, the control circuit activates the low pressure fuel pump.